Sonic drill head

ABSTRACT

A sonic drill head comprising an outer housing, an isolation system, a sine generator and a spindle. The sine generator generates a linear sinusoidal vibration force through the rotation of a plurality of eccentric masses. The sine generator is configured to translate the linear sinusoidal force to the spindle in a direction corresponding to the spindle&#39;s axis of rotation. The sine generator supports the spindle within the housing such that the spindle is free to rotate about the spindle axis. The spindle is generally a hollow tube section thereby allowing the passage of drilling fluid, mud, cuttings, and/or tooling. The isolation system generally reduces the transfer of the vibration force generated by the sine generator to the outer housing, yet is able to transfer an applied thrust force from the outer housing to the sine generator.

CROSS-REFERENCE TO RELATED APPLICATIONS

None.

BACKGROUND OF THE INVENTION

The present invention is generally directed to a sonic drill head. Sonicdrill heads generally impart a vibratory force and send high frequencyresonant vibrations down a drill string to a drill bit. The sonic drillhead combines this vibratory force with a slow rotation of the drillstring to ensure that the energy applied and wear resulting fromdrilling are evenly distributed at the drill face. Vibration generatorsfor sonic drilling may be housed with a rotary drive or may be a standalone component of a drill string. The frequency of vibration isgenerally between 50 and 120 hertz (cycles per second) and the drilloperator controls the frequency of the vibrations to match the naturalfrequency of the drill string to take advantage of the resonance effectsof the drill string and/or to suit the specific conditions of thesoil/rock geology. The resonance created at the selected frequencymagnifies the amplitude of the drill bit thereby allowing for fast andeasy penetration through many geological formations.

Since sonic drilling obtains its results through the combination ofresonant vibrations superimposed upon a slow drill rotation, sonic drillheads are generally designed and constructed with no consideration ofoperating the drill with a high-speed spindle rotation suitable fortraditional diamond core drilling or other rotary drilling methods.Sonic drill heads known in the art do not efficiently provide theability to rotate the spindle at high speeds without vibration such thatthe drill head can additionally perform traditional diamond core orother rotary drilling methods. Further, either the vibration generatoror the rotation drive of existing sonic drill heads is often locateddirectly above the spindle within the drill head that receives the drillstring. In one existing drill head, the vibration generator or rotationdrive is directly above the spindle thereby preventing the passage ofwater, drilling fluids, mud, cuttings and/or tooling, or any othermaterials through the top spindle to or from the drill string and drillhead. Other existing drill heads have been adapted to provide a narrowpassageway to facilitate the injection of water or drilling fluid to aidin drilling. The passage of materials through the spindle to or from thedrill string is generally not a consideration in sonic drill headscurrently in use because the slow rotation of sonic drilling does notgenerally generate the same drilling conditions of other higher speedrotary drilling methods that often require passage of materials throughthe drill string to aid in the drilling process. As a result, existingsonic drill heads do not currently allow the passage of cuttings throughthe top of the drill head that are desirable when performing deepdrilling. Further, existing sonic drill heads do not currently allow thepassage of downhole instrumentation, and/or tooling through the top ofthe drill head which may be desirable when monitoring downholeconditions while drilling.

Therefore, a need exists in the art for a sonic drill head that allowsan operator to perform both sonic drilling—slow rotary motionsuperimposed to the vibratory motion—and high speed rotary drilling.Accordingly, an additional need exists for a sonic drill head thatallows the passage of drilling fluids, mud, cuttings or tooling to beintroduced or removed as necessary through the top of the drill head.

BRIEF SUMMARY OF THE INVENTION

The present invention is generally directed to a sonic drill headcomprising an outer housing, an isolation system, a sine generator and aspindle. The isolation system is within the housing and generallyreduces the transfer of the vibration force generated by the sinegenerator to the outer housing, yet is able to transfer an appliedthrust force from the outer housing to the sine generator. The sinegenerator is also within the housing and generates a linear sinusoidalvibration force through the rotation of a plurality of rotors, eachrotor having an eccentric center of mass. The rotors are driven bymeshing bevel gears and, as a result, adjacent rotors rotate in oppositedirections. In one embodiment, the eccentric weights are synchronizedsuch that the eccentric masses reach top-dead-center andbottom-dead-center simultaneously creating a linear sinusoidal force.Further, any horizontal components of force generated by the rotation ofthe eccentric masses generally cancel out because the rotors rotate inopposite directions thereby resulting in a purely linear vertical forcegeneration. The sine generator is configured to translate this linearsinusoidal force and/or the thrust force to the spindle. The directionof force generally corresponds to the spindle's axis of rotation.

The sine generator is configured to support the spindle within thehousing such that the spindle is free to rotate about the spindle axisrelative to the sine generator, yet the sine generator still transfersthe linear sinusoidal force to the spindle along the spindle's axis ofrotation. The sine generator is configured to allow the spindle to passthrough the sine generator and the spindle may protrude outside theouter housing in some embodiments. This configuration allows the spindleto rotate both at low speeds used for sonic drilling and high speedsused for diamond core or other rotary drill methods. Further, anembodiment of the present invention includes the spindle being acontinuous and hollow tube section allowing the introduction or removalof drilling fluid, mud, cuttings, and/or tooling, or other drilling aidsinto or out of the drill string through the top of the spindle.

Other aspects and advantages of the present invention will be apparentfrom the following detailed description of the preferred embodiments andthe accompanying drawing figures.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

The accompanying drawing forms a part of the specification and is to beread in conjunction therewith, in which like reference numerals areemployed to indicate like or similar parts in the various views, andwherein:

FIG. 1 is a cross-sectional view of a sonic drill head in accordancewith one embodiment of the present invention;

FIG. 2 is a front perspective view of a sine generator and isolationsystem in accordance with one embodiment of the present invention;

FIG. 3 is a top perspective view of the rotors and vibration drivesystem in accordance with one embodiment of the present invention;

FIG. 4 is a cross-sectional view of the rotors in accordance with oneembodiment of the present invention;

FIG. 5 is a cross-sectional view taken along the line 5-5 of a torquetransfer assembly in accordance the embodiment of the present inventionin FIG. 1.

FIG. 6 is a cross-sectional view of the piston assembly in accordancewith one embodiment of the present invention;

FIG. 7 is a cross-sectional view of a water swivel in accordance withone embodiment of the present invention;

FIG. 8A is a cross-sectional view of an anti-rotation assembly inaccordance with one embodiment of the present invention; and

FIG. 8B is a cross-sectional view taken along the line 8B-8B of ananti-rotation assembly in accordance with the embodiment shown in FIG.8A.

DETAILED DESCRIPTION OF THE INVENTION

The following detailed description of the invention references theaccompanying drawing figures that illustrate specific embodiments inwhich the invention can be practiced. The embodiments are intended todescribe aspects of the invention in sufficient detail to enable thoseskilled in the art to practice the invention. Other embodiments can beutilized and changes can be made without departing from the scope of thepresent invention. The present invention is defined by the appendedclaims and the description is, therefore, not to be taken in a limitingsense and shall not limit the scope of equivalents to which such claimsare entitled.

Now turning to FIG. 1, a sonic drill head 10 comprises an outer housing12, a sine generator 14, a spindle 16, and an isolation system 18. Outerhousing 12 generally encloses the other components of sonic drill head10 including sine generator 14, spindle 16 and isolation system 18. Anembodiment of outer housing 12 may be assembled such that the entireouter housing 12 or a portion thereof maybe removed to allow access tosine generator 14, spindle 16, or isolation system 18 for upkeep,replacement, repair, other maintenance or any other reason required inthe art. Outer housing 12 can be a single cast or molded piece or,alternatively, a plurality of component pieces coupled together toenclose sine generator 14, spindle 16 and isolation system 18. Outerhousing 12 of the present invention can be made from any material knownin the art including steel, iron, titanium, aluminum, industrialplastics, fiber glass, carbon-fiber composite, any other industrialmaterial having the required strength properties, or any combinationthereof.

Sine generator 14 is driven by a vibration drive system 20 and comprisesa motor 22, a gearing system 24, and drive shaft 26. Motor 22 includesan output shaft 28. Motor 22 can be any motor type known in the artincluding hydraulic, pneumatic, electric, gas turbine engine, or aninternal combustion engine. Output shaft 28 removably and drivinglyengages gearing system 24 described in detail below. Gearing system 24is configured to drivingly engage drive shaft 26 and increase the speedof rotation of drive shaft 26 when compared to the rotation speed ofoutput shaft 28. One embodiment of gearing system 24 is a planetarygearing system comprising a ring gear 30, a plurality of planetary gears32, and a sun gear 34. Gearing system 24 can be configured to any speedincreasing ratio known in the art as necessary to obtain the desiredvibration force and frequency. An embodiment of gearing system of thepresent invention can incorporate a speed increasing ratio in the rangebetween one and one-half to one (1½:1) and six to one (6:1). Anembodiment of gearing system 24 of the present invention incorporates aspeed increasing ratio around three to one (3:1).

FIG. 1. illustrates an embodiment of drive shaft 26 having a first end36 and a second end 38 wherein first end 36 and second end 38 of driveshaft 26 include crowned splines 40. The crowned splines 40 of first end36 of drive shaft 26 allow for engagement with mating splines containedin sun gear 34. First end 36 of drive shaft 26 is retained in sun gear34 through a pair of spring loaded spherical bearings 42. The crownedsplines 40 of second end 38 of drive shaft 26 allow for matingengagement with splines contained in a bevel gear 44 coupled to aneccentric rotor 46 of sine generator 14. The crowned splines 40 allowdrive shaft 26 to transmit power from sun gear 34 to bevel gear 44 whilebevel gear 44 and eccentric rotor 46 are vibrating with sine generator14.

Sine generator 14 generally comprises a top plate 48, a bottom plate 50,and a plurality of eccentric rotors 46, each rotor 46 within a rotorhousing 52. Each rotor housing 52 is positioned between top plate 48 andbottom plate 50. Rotor housing 52 is generally coupled to top plate 48and bottom plate 50. Eccentric rotor 46 is journaled for rotation withinrotor housing 52 upon rotor bearings 54. Eccentric rotor 46 has aneccentric mass 56 that offsets the center of mass of eccentric rotor 46from the center of rotation of eccentric rotor 46 by a selected amount.Eccentric rotor 46 further includes an inside face 58 and an outsideface 60. Bevel gear 44 is coupled to the inside face 58 of eccentricrotor 46 using any method known in the art. Through out thisdescription, the term “coupling” shall be interpreted to include allcoupling methods known in the art including, but not limited to: bolts,screws, pins, rivets, welds, retention rings, compression rings, or anyother mechanical coupling method known in the art. Alternatively, bevelgear 44 may be cast with eccentric rotor 46 as one component piece.

Sine generator 14 and its components described above can be of anymaterial known in the art including steel, iron, titanium, aluminum,industrial plastics, fiber glass, carbon-fiber composite, any otherindustrial material having the required strength properties, or anycombination thereof.

Spindle 16 includes a first end 62 and a second end 64. First end 62 andsecond end 64 generally define spindle axis 66. Spindle 16 is rotatedabout spindle axis 66 during drilling operations. Spindle 16 is drivenby at least one spindle motor 68. An output shaft 70 of spindle motor 68operably engages a pinion gear 72. In one embodiment, output shaft 70 issplined and pinion gear 72 includes a mating splined inner face 73 toalign with and receive output shaft 70. Any other mechanical couplingmethods known in the art, including those described above, may beinstituted such that output shaft 70 drivingly engages pinion gear 72.Pinion gear 72 engages rotation gear 74 that transfers the torquegenerated by spindle motor 68 to spindle 16 through torque transferassembly 76 thereby causing rotation of spindle 16 about spindle axis66. An embodiment of the present invention includes two spindle motors68, each spindle motor 68 driving a pinion gear 72 that is drivinglyengaged with rotation gear 74. Rotation gear 74 and torque transferassembly 76 are journaled for rotation relative to outer housing 12 uponrotation drive bearings 78. Rotation drive bearings 78 are generallyroller bearings, but can be any bearing type or configuration known inthe art that facilitates the rotation of spindle 16 with respect toouter housing 12.

Spindle 16 is mounted to sine generator 14 with upper spindle bearing 80and lower spindle bearing 82. Spindle bearings 80, 82 allow independentrotary motion of spindle 16 with respect to a center 84 of sinegenerator 14. Spindle bearings 80, 82 also the transfer the vibrationforce from sine generator 14 to spindle 16. The spindle bearingconfiguration of the present invention allows sonic drill head 10 to beutilized for sonic drilling—the superposition of slow rotation withvibration upon spindle 16—and traditional high speed rotary drillingincluding, but not limited to diamond core, and other rotary drillmethods known in the art. One embodiment of the present inventionincludes spindle bearings 80, 82 being spherical roller thrust bearings.Any other bearing type or configuration known in the art that supportsspindle 16 upon sine generator 14 while allowing for free rotation ofspindle 16 with respect to sine generator 14 and also transferring thevibratory force from sine generator 14 to spindle 16 is within the scopeof the present invention. In one embodiment of the present invention,the spindle bearing preload is adjusted by means of a spindle lock nut83 and thrust sleeve 85. The nut contains jack screws 87 that eachindividually contribute to the entire developed preload, therebyeliminating the need to torque the spindle lock nut 83. Tightening ofthe jack screws 87 creates an upward acting force on spindle 16 and anequal and opposite downward acting force on the thrust sleeve 85 andassociated components which places upper and lower spindle bearings 80,82 into compression, or preload, against sine generator 14.

Spindle 16 generally is a continuous member having a hollow crosssection as shown in FIG. 1. Spindle 16 is a member generally havingcircular cross-section; however, any member shape in the art known to beused as a spindle 16 may be used. One embodiment of spindle 16 includesa one piece hollow shaft. An alternative embodiment of spindle 16 mayinclude a plurality of members coupled together having an uninterruptedhollow cross-section. An embodiment of the present invention may includespindle 16 having a solid cross-section. An embodiment of spindle 16includes first end 62 and second end 64 of spindle 16 protruding throughthe outer housing 12. Embodiments of the present invention may includespindle 16 protruding out of the top or the bottom of the outer housing,or both. The continuous hollow cross section of spindle 16 is configuredfor the addition or removal of cuttings, materials, lubricants, tools,instrumentation, or other drilling aids.

Common materials that may be introduced into drilling string throughfirst end 62 of spindle 16 may include drilling fluid, mud, and tooling(not shown). In addition, materials including drilling fluid, mud,tools, or cuttings resulting from the drilling process may be removedthrough the first end 62 of spindle 16. It will be appreciated by one ofskill in the art that any of a number of materials, tools, or otherdrilling aids may be introduced into or removed from the drill stringthrough first end 62 of spindle 16. When no materials, tools or drillingaids are to be removed or introduced through first end 62 of spindle 16,an embodiment of the present invention may include a cap 86 removablycoupled to first end 62 of spindle 16 or to outer housing 12 as shown.

The second end 64 of spindle 16 can be configured to receive a drillstring (not shown). Any drill string known in the art for sonicdrilling, diamond core drilling, rotary drilling, or any other drillingmethod known in the art suitable for use with sonic drill head 10 iswithin the scope of the present invention. There are many connectiontypes known in the art to removingly couple a drill string to second end64 of spindle 16, all of which a person of skill in the art wouldappreciate to be within the scope of the present invention.

Spindle 16 is generally journaled for rotation and axial movement withrespect to outer housing 12 of sonic drill head 10. One embodiment ofthe present invention includes first end 62 and second end 64 journaledthrough an upper hydrostatic bearing 88 proximate first end 62 ofspindle 16 and a lower hydrostatic bearing 90 proximate second end 64 ofspindle 16. The hydrostatic bearings 88, 90 float spindle 16 on a thinfilm of oil that is pumped in under pressure. Hydrostatic bearings 88,90 contain a plurality of inner pockets (not shown) that are fed withsupply oil through a metering orifice. In one embodiment, a clearancegap 92 between the spindle journal 94 and the bearing inner diameter(not shown) is maintained to restrict oil leakage and prevent reducedbearing capacity. Hydrostatic bearings 88, 90 have a low coefficient offriction and virtually unlimited wear life. An alternate embodiment (notshown) includes using commercially available non-hydrostatic slidebearings comprising a steel base layer, a bronze mid-layer and alow-friction polymer top-layer. This slide bearing may or may not belubricated. A person of skill in the art will appreciate that thepresent invention is not limited to use of hydrostatic bearings tofacilitate rotation and axial translation of spindle 16 with respect toouter housing 12 as described herein, but any traditional slidingbearing that facilitates this relative movement now known or hereafterdeveloped is within the scope of the present invention.

Spindle 16 and its components described above can be of any materialknown in the art including steel, iron, titanium, aluminum, industrialplastics, fiber glass, carbon-fiber composite, any other industrialmaterial having the required strength properties, or any combinationthereof.

FIG. 1 further illustrates an embodiment of isolation system 18.Isolation system 18 generally isolates the high amplitude vibratorymotion of spindle 16 from outer housing 12 wherein outer housing 12remains relatively stationary. An embodiment of the isolation system 18of the present invention includes a plurality of assemblies comprisingan air piston 96 and a cylinder 98 that provide separation of thestationary and moving parts with a cushion of compressed air 100. Anembodiment of the present invention includes twelve (12) air piston 96and cylinder 98 assemblies. Embodiments of isolation system 18 of thepresent invention can alternatively include, but are not limited to:mechanical springs or shocks, air springs or shocks, hydraulic springsor shocks, fluid dampers, passive or active mass dampers, or any othersystem known in the art to isolate the vibration generated by sinegenerator 14 from outer housing 12.

An embodiment of the present invention may also include an isolationsystem 18 and sine generator 14 that translates a thrust force duringdrilling from the outer housing 12 to spindle 16. An embodiment of thepresent invention includes piston 96 and cylinder 98 assembliestranslating thrust forces from the outer case to the drill spindleduring drilling. Properly sized and placed inlet and exhaust porting(not shown) within cylinders 98 cause sine generator 14 to seek acentered position within outer housing 12 when acted upon by externalforces. An embodiment of isolation system 18 may also include a bumper102 to limit the motion of sine generator 14 to reduce or prevent damageto outer housing 12 or piston 96 in the event of a force overload.Bumper 102 can be any configuration and material known in the art toreduce or prevent damage during the impact of two members. Embodimentsof bumper 102 may include mechanical springs or elastomeric pads.

An embodiment of isolation system 18 further includes an upper pistonassembly 104 proximate top plate 48 of sine generator 14 and a lowerpiston assembly 106 proximate bottom plate 50 of sine generator 14wherein upper piston assembly 104 and lower piston assembly 106 arealigned. Upper piston assembly 104 and lower piston assembly 106 furtherinclude a sealing member 108 that engages a wall 110 of cylinder 98 toform a substantially air tight seal. Sealing member 108 can be anymaterial having a resiliency to withstand many cycles of vibratorymotion relative wall 100 of cylinder 98 and maintain a substantiallyair-tight seal including, but not limited to: cast iron, aluminum,steel, brass, rubber, polymeric composite blends, fiber-reinforcedcomposites, and elastomeric materials. An embodiment uses a cast ironsealing member 108.

Isolation system 18 may further include a spacer 112 between top plate48 and bottom plate 50 of sine generator 14 and a threaded rod 114through apertures (not shown) in upper piston assembly 104, top plate48, spacer 112, bottom plate 50, and lower piston assembly 106 as shownin FIG. 2. The present invention is not limited to a threaded rod, butany smooth rod having threading at each end may be used. Further, a nut116 engages each end of threaded rod 114 and is tightened therebyclamping upper piston assembly 104, top plate 48, spacer 112, bottomplate 50, and lower piston assembly 106 into a substantially rigidassembly. This assembly must transfer force axially in the direction ofvibration. Alternatively, any other method of assembling upper piston104, top plate 48, spacer 112, bottom plate 50, and lower piston 106such that they form a substantially rigid member capable of transferringforce in the direction of vibration is within the scope of the presentinvention, including threading components such that they matingly engagewith the other components as required or welding components together.

Isolation system 18 and its components described above can be of anymaterial known in the art including steel, iron, titanium, aluminum,industrial plastics, fiber glass, carbon-fiber composite, any otherindustrial material having the required strength properties, or anycombination thereof.

Now turning to FIG. 2, one embodiment of sine generator 14, spindle 16and isolation system 18 is further illustrated. This embodiment includessix rotors 46, each rotor 46 journaled for rotation in a rotor housing52. A plurality of rotor bearings 54 facilitates the rotation of rotor46 within rotor housing 52. One embodiment of the present inventionincludes rotor bearings 54 being angular contact rolling elementbearings mounted in a back to back arrangement. A person of skill in theart will appreciate that the present invention is not limited to aparticular rotor bearing type, but any known bearing types in the artare within the scope of the present invention. In one embodiment, rotorhousing 52 is coupled to both top plate 48 and bottom plate 50 of sinegenerator 14 with six bolts 118 at each plate 48, 50 as shown. Thecoupling of rotor housing 52 to both plates 48, 50 of sine generator 14shall not be limited to a bolted connection, but can be any couplingmethod known in the art using any number of fasteners including: bolts,screws, pins, rivets, welds, retention rings, compression rings, clamps,or any other mechanical coupling method known in the art.

FIG. 2 also demonstrates an embodiment of top plate 48 and bottom plate50 that further includes two stiffener ribs 120 proximate each couplingposition of housing 52. Ribs 120 generally stiffen plates 48, 50 at ornear where rotor housing 52 applies the vibration force to plates 48,50. Further, an embodiment of top plate 48 and bottom plate 50 includesa stiffener 122 proximate a piston housing 124 that receives upperpiston 104 in top plate 48 and lower piston 106 in bottom plate 50wherein piston housing 124 is proximate an outside face 126 of topplates 48 or proximate an outside face 127 of bottom plate 50. Ribs 120generally extend from outer face 126 or 127 to an inner face 128 of sinegenerator 14 and are integral with top plate 48 or bottom plate 50.Stiffeners 122 generally extend from piston housing 124 to inner face128 in a radial direction from center 84 of sine generator 14 on eitherplate 48, 50. Embodiments of the present invention may include center 84being located on spindle axis 66 of spindle 16 as shown.

FIG. 2 illustrates an embodiment of the present invention wherein thesix rotors 46 are in a hexagonal shape, extending radially from spindleaxis 66. The layout of rotors 46 forms an aperture (not shown) thatgenerally corresponds with inner face 128 of sine generator 14. Thisconfiguration of sine generator 14 allows spindle 16 to be a continuousmember that extends through sine generator 14 as shown. FIG. 2 alsoillustrates the location of upper spindle bearing 80 with respect to topplate 48. One embodiment of the present invention includes upper andlower spindle bearings 80, 82 being a spherical thrust bearing assembly.One embodiment includes spindle bearings 80, 82 having a cage 130 madeof light weight polymer. The lightweight polymer helps to eliminatedamage caused by inertial effects. An alternative embodiment includescage 130 being made from lightweight, high strength steel. Further, thegeometry of the cage is modified to minimize axial clearance withrespect to the bearing elements, thereby reducing the impact forcescause by the high level of vibration.

FIG. 2 further illustrates an embodiment of torque transfer assembly 76that includes a plurality of lobes 132 wherein the lobes 132 are coupledto or integral with a continuous ring 134. Other members of torquetransfer assembly (not shown) drivingly engage lobes 132 causing thelobes 132 and continuous ring 134 to rotate about spindle axis 66.Continuous ring 134 is configured to engage spindle 16 such that torqueapplied to continuous ring 134 causes the rotation of spindle 16 aboutspindle axis 66.

FIG. 2 further illustrates an embodiment of isolation system 18 of thepresent invention. In the illustrated embodiment, upper piston 104 isreceived into piston housing 124 of top plate 48 and lower piston 106 isreceived into piston housing 124 of bottom plate 50. Further, spacer 112is located between top plate 48 and bottom plate 50. One embodimentincludes spacer 112 being received into a recess in the surface of topand bottom plates 48, 50 configured receive spacer 112. One embodimentincludes spacer 112 bearing directly on top and bottom plates 48, 50.FIG. 2 also further illustrates sealing member 108 on an outside face136 of piston 96.

Now turning to FIG. 3, components of vibration drive system 20, gearingsystem 26 and the configuration of eccentric rotors 46 of one embodimentof the present invention are illustrated. FIG. 3 illustrates gearingsystem 26 including a ring gear 30, three planet gears 32, a sun gear34, and a ring gear drive assembly 135 wherein ring gear drive assembly135 further comprises input housing 137, radial arms 139, and attachmentring 141. Motor 22 turns output shaft 28 that provides input torque toring gear assembly 30. Output shaft 28 includes radial extending teethor splines that matingly engage teeth or splines on an inner face 143 ofinput housing 137 of ring gear assembly 135. The present invention mayinclude embodiments wherein input housing 137, radial arms 139 andattachment ring 141 of ring gear assembly 135 are stand alone partscoupled together, integrally cast into one part, or any combinationthereof. A first end 145 of radial aims 139 are rigidly coupled to orcast integral proximate housing 137 and radial arms 139 extend radiallyfrom housing 137 wherein a second end 147 of radial arms 139 isproximate attachment ring 141. Radial arm 139 may be one piece or aplurality of components coupled together. An embodiment of the presentinvention may alternatively use a substantially solid formed plateinstead of the radial arms 139 to transfer torque from input housing 137to attachment ring 141. Attachment ring 141 is generally coupled to orcast integral with ring gear 30. Ring gear 30 is drivingly engaged withthree planetary gears 32. The axis of rotation for each planetary gear32 is held static and the planetary gears 32 drivingly engage sun gear34 and create output torque that rotates sun gear 34.

Sun gear 34 engages and thereby causes the rotation of drive shaft 26.First end 36 of drive shaft 26 may have crowned splines 40 thatremovably engage with mating splines 138 of sun gear 34. Second end 38of drive shaft 26 engages with a driven bevel gear 140. Driven bevelgear 140 drivingly engages two adjacent bevel gears 44. FIG. 3illustrates an embodiment of the present invention wherein the six bevelgears 44, 140, eccentric rotors 46, and housings 52 are configured in ahexagonal distribution around the center 84 of sine generator 14. Thisembodiment further includes each bevel gear 44 being paired with anopposite bevel gear 44, resulting in three pairs of bevel gears. Eachpair of bevel gears 44 is aligned along a first pair line 142, a secondpair line 144, and a third pair line 146. One embodiment of the presentinvention includes the pair lines 142, 144, 146 intersecting at a commonpoint 148. An embodiment of the present invention includes lines 142,144, 146 all including an intersecting angle 150 of sixty (60) degrees.Other intersecting angles are also within the scope of the presentinvention. An embodiment of the present invention includes common point148 being on spindle axis 66.

In general, the six bevel gears 44 operate in series; therefore,rotating driven bevel gear 140 causes the rotation of all the otherbevel gears. Each bevel gear 44, 140 are integral with or coupled to aneccentric rotor 46 within rotor housing 52 and the rotation of eachbevel gear 44 causes the rotation of each rotor 46. An embodiment ofbevel gear 44 includes spiral bevel gear although a person of skill inthe art will appreciate any of a number of bevel gear types andconfigurations known in the art are within the scope of the presentinvention.

FIG. 4 illustrates an embodiment of sine generator 14 of sonic drillhead 10 wherein eccentric rotor 46 axis of rotation 152 is tilted fromhorizontal. This embodiment results in all six rotors 46 having anindividual axis of rotation 148. FIG. 4 further illustrates anembodiment of the sine generator 14 of the present invention whereinrotors 46 are synchronized with bevel gears 44 such that all eccentricmasses 56 reach top-dead-center and bottom-dead-center simultaneously.Specifically, it can be seen in FIG. 4 that a first eccentric mass 154of a first rotor 156 and a second eccentric mass 158 of a second rotor160 are both at bottom-dead-center. In this embodiment, the othereccentric masses 56 of the other two rotors 162 shown in FIG. 4 and thetwo rotors not shown are also at bottom-dead-center. When the eccentricmasses 56 of all rotors 46 are synchronized and rotate about theirindividual axis of rotation 152, the forces in the top-dead-centerdirection and bottom-dead-center direction are additive creating alinear sinusoidal force in a direction corresponding withtop-dead-center and bottom-dead-center. No resultant horizontal force ispresent because bevel gears 44 cause adjacent rotors 46 to rotate inopposite directions and, as a result, any horizontal force componentscreated by the rotation of eccentric rotors 46 cancel out when an evennumber of eccentric rotors 46 are present as shown.

Now turning to FIG. 5, an embodiment of torque transfer assembly 76 ofsonic drill head 10 is illustrated. Torque transfer assembly 76generally transfers the drive force generated by at least one spindlemotor 68 to spindle 16. FIG. 5 illustrates an embodiment of sonic drillhead 10 powered by two spindle motors 68. Output shafts 70 of eachspindle motor 68 are shown in FIG. 5 to be splined and engaging a matingsplined inside face 73 of pinion gear 72. Pinion gears 72 are drivinglyengaged with rotation gear 74. The relative size difference between thepinion gears 72 and rotation gear 74 determines the torque increasingratio. Embodiments of the present invention include a torque increasingratio being in the range between one and one-half to one (1½:1) and tento one (10:1). An embodiment of the present invention may have a torqueincreasing ratio of generally around five to one (5:1). Spindle motor 68operates at its highest displacement during sonic drilling providing alow speed output with high torque. Spindle motor 68 may alternativelyoperate at its minimum displacement to perform diamond core or otherknown high speed rotary drill methods providing a high speed output withlow torque.

Torque is generally transferred from the spindle motor 68, pinion gear72, and rotation gear 74 to spindle 16 through torque transfer assembly76 in the present invention. An embodiment of the driving half of torquetransfer assembly 76 as shown in FIG. 5 includes a plurality of housings164 coupled to rotation gear 74 wherein a pair of bearing pads 166 arecoupled to each housing 164. One embodiment includes bolting housing 164to rotation gear 74, but any coupling method known in the art including:bolts, screws, pins, rivets, welds, retention rings, compression rings,or any other mechanical coupling method known in the art is within thescope of the present invention. An embodiment of the driven half oftorque transfer assembly 76 as shown includes a plurality of lobes 132that radiate outward from an outer face 168 of continuous ring 134.Lobes 132 may be evenly spaced around circumference of continuous ring134 or, alternatively, may be unevenly spaced. Housings 164 areconfigured on rotation gear 74 to matingly engage lobes 132 whetherlobes 132 are evenly or unevenly spaced.

Continuous ring 134 is shown to have a splined inner face 170. Splinedinner face 170 of continuous ring 134 mates with splines 172 integral tospindle 16. Splines 172 not only transfer torque, but are configured toallow axial slip of ring 134 and thrust sleeve 85 to effect preload ofspindle bearings 80, 82. Each lobe 132 is configured to be locatedbetween two housings 164 and bear against a pair of bearing pads 166,yet remain axially translatable with respect to the bearing pad 166pairs and housings 164. One bearing pad 166 engages with a side 174 ofeach lobe 132 for the purpose of transferring torque in two directions.The embodiment shown in FIG. 5 includes eighteen (18) bearing pads 166coupled to nine (9) housings 164 and nine (9) lobes 132 to complete thetransfer of torque from the spindle motor(s) 68 to spindle 16.

An embodiment of an upper piston assembly 104 of the present inventionis shown in FIG. 6. Lower piston assembly 106 can be constructed in asubstantially identical manner. Upper piston assembly 104 as shownincludes an upper piston support 176, lower piston support 178, andpiston 180. Upper piston support 176 includes an upper support flange182 having a lower surface 184. Lower piston support 178 includes alower support flange 186 having an upper surface 188. Piston 180includes a top surface 190, a bottom surface 192, an inner aperture 194,and outer surface 196. Upper piston support 176 passes through the inneraperture 194 of piston 180 and nests in lower piston support 178 asshown and piston 180 is thereby sandwiched between lower surface 184 ofupper piston support 176 and upper surface 188 of lower piston support178. Upper piston support 176 and lower piston support 178 areconfigured such that rod 114 passes through both members and upperpiston support 176 is coupled to lower piston support 178 and securedthereto by nut 116 as shown.

One embodiment of piston assembly 104, 106 includes a clearance gap 198between lower surface and a sealing member 108. Clearance gap 198 may beconfigured to allow a lubricant to be introduced between the pistonsupports 176, 178 and piston 180. An upper o-ring 200 nests in lowersurface 194 of upper piston support 176 and a lower o-ring 202 nests inupper surface 188 of lower piston support 178 as shown wherein o-rings200, 202 retain the lubricant. Clearance gap 198 allows the upper andlower piston supports 176, 178 to shift relative to piston 180. Thisembodiment provides the piston 180 interface with cylinder wall 110 toreact and resist torsion forces developed in spindle bearings 80, 82.One embodiment includes a clearance gap of 0.010 inches, though any gapproviding lubrication and relative slip of piston 180 with upper support176 and lower support 178 is within the scope of the present invention.In one embodiment of the present invention, isolation system 18 performsat least three functions including, but not limited to vibrationisolation, thrust force transfer, and torque resistance.

Outer surface 196 of piston 180 may include sealing member 108 nestedinto a grove or housing machined into outer surface 196 as shown.Further piston 180 may also include a lubrication metering orifice 204located in at least one location on outside surface 196 of piston 180.Lubrication metering orifice 204 allows for manual or automatedmeasurement of lubricant level or operating temperature. Outer surface196 may also include a lubrication groove 206 as shown to lubricate therelative movement between outer surface 196 and cylinder wall 110. Anylubrication method know in the art to lubricate piston 180 fortranslation relative to cylinder wall 110 may be implemented to supplyliquid or dry lubricants to outer surface 196 and the piston assembly104, 106.

An embodiment of the present invention including water swivel 206 at thefirst end 62 of spindle 16 is shown in FIG. 7. Water swivel 206generally includes a stator 208, a rotor 210, and a bonnet 212. Stator208 is generally configured to be a non-rotating component thatfacilitates fluid entry into spindle 16 as shown. Stator 208 generallyincludes a hollow cross-section configured to receive a pressure hosefitting as shown and to facilitate the passage of fluid in or out ofstator 208. The shape of stator 208 may be any shape known in the art,including the configuration shown in FIG. 7. Stator 208 may include ahousing 214 that receives seal 216, wherein seal 216 may includebearings 218 that facilitate the relative rotation of rotor 210 withrespect to stator 208. Stator 208 may also include grease groove 220 asshown.

Rotor 210 is generally attached to and configured to rotate with spindle16. Rotor 210 may include a first end 222, a second end 224, a flange226, a polished ceramic liner 228, a wiper 230, and a groove 232 thatreceives a static o-ring 234. Rotor 210 is generally configured to bereceived into first end 62 of spindle 16 substantially as shown. Oneembodiment includes rotor 210 being coupled to spindle lock nut 83 withjack screws 87 wherein spindle lock nut 83 is threaded onto first end 62of spindle 16.

An embodiment of rotor 210 may include a hollow cross section configuredto receive stator 208 as shown. The hollow cross-section also allowsfluid to pass through the ends of rotor 210. In this embodiment, statico-ring 234 is configured to provide a fluid-tight seal between the rotor210 and the spindle 16 to prevent any introduced water from beingunwantingly expelled out of first end 62 of spindle 16. Polished ceramicliner 228 is configured to provide a surface that offers reducedfriction during the rotation of rotor 210 about stator 208 while incontact with seal 216 of stator 208. An embodiment of rotor 210 may alsoinclude wiper 230 generally configured to exclude dirt, dust, or othercontaminants from affecting the seal between stator 208 and rotor 210.As shown in FIG. 7, wiper 226 is proximate an inner surface 236 of rotor210 and rests against an outer surface 238 of stator 208.

An embodiment of the present invention may include bonnet 212 thatcovers the stator 208 and rotor 210 as shown. Bonnet 212 may beremovably coupled to stator 208. Further, bonnet 212 may be removablycoupled to outer housing 12. An embodiment of bonnet 212 includes accessapertures 240 allowing an operator to rotate jack screws 87 therebyadjusting the pre-load of spindle bearings 80, 82 as described abovewithout removing the bonnet for minimal interruption of the operation ofthe sonic drill head 10 of the present invention.

An embodiment of the sonic drill head 10 of the present inventionillustrated in FIGS. 8A and 8B may further include at least oneanti-rotation assembly 242 to resist torsion forces developed in spindlebearings 80, 82 and thereby prevent rotational displacement of sinegenerator 14. Anti-rotation assembly 242 includes a reaction bar 244coupled to upper sine generator plate 48 and lower sine generator plate50, a first substantially vertical bearing pad 246 and a secondsubstantially vertical bearing pad 248 opposite said first bearing pad246 separated by a distance D. Reaction bar 244 includes a firstsubstantially vertical face 250, a second substantially vertical face252 opposite first vertical face 250, a thickness T of material definedby first vertical face 250 and second vertical face 252, and a length L.Length L is generally such that reaction bar 244 spans continuouslybetween upper and lower sine generator plates 48 and 50. Thickness T isgenerally slightly less than distance D such that reaction bar 244slides vertically between first bearing pad 246 and second bearing pad248, but substantial horizontal movement of reaction bar in bothdirections is resisted by bearing pads 246 and 248. First and secondvertical faces 250, 252 of reaction bar 244 are cast or machined smoothso as to easily slide vertically relative to first and second bearingpads 246, 248 thereby allowing substantially frictionless verticaldisplacement of sine generator 14 relative to outer housing 12.

First bearing pad 246 engages first vertical face 250 of reaction bar244 and second bearing pad 248 engages second vertical face 252 ofreaction bar 244 to prevent rotation of the sine generator 14 withinouter housing 12 due to the friction of spindle bearings 80, 82 whenspindle 16 is rotating. In one embodiment, first bearing pad 246 andsecond bearing pad 248 are supplied with lubricating oil through an oilinlet hole 254 within the pad. The oil inlet hole 254 communicates witha plurality of serrations or channels (not shown) in first and secondbearing pads 246, 248. The serrations or channels distribute the oiluniformly over the entire surface of interaction between bearing pads246, 248 and vertical faces 250, 252 of reaction bar 244. First bearingpad 246 and second bearing pad 248 are coupled to anti-rotation housing256. Anti-rotation housing 256 is generally coupled to outer housing 12as shown. An external hose 258 and pump (not shown) supplies thelubricating oil to first and second bearing pads 246 and 248. Thus,anti-rotation assembly 242 allows for virtually frictionless verticaltranslation of sine generator 14 relative to outer housing 12, yeteffectively prevents sine generator 14 from rotating about spindle axis66 due to the frictional resistance of spindle bearings 80, 82.

From the foregoing, it may be seen that the sonic drill head of thepresent invention is particularly well suited for the proposed usagesthereof. Furthermore, since certain changes may be made in the aboveinvention without departing from the scope hereof, it is intended thatall matter contained in the above description or shown in theaccompanying drawing be interpreted as illustrative and not in alimiting sense. It is also to be understood that the following claimsare to cover certain generic and specific features described herein.

We claim:
 1. A vibratory drill head comprising: a housing; a spindlemounted to said housing for axial rotation, said spindle presenting apassage therethrough extending between upper and lower ends of saidspindle to allow materials to move through said spindle; a sinegenerator in said housing coupled to said spindle between said upper endand said lower end of said spindle in a manner to apply a sinusoidalvibration to said spindle, wherein said sine generator comprises sixeccentric rotors radially distributed about a center point, each saidrotor having an eccentric weight, wherein all said eccentric weightsreach top dead center and bottom dead center simultaneously, whereineach of said six eccentric rotors include an axis of rotation, whereinthe six axes of rotation are spaced radially equidistant, and whereineach of said axes of rotation are tilted from horizontal; and anisolation mechanism in said housing acting between said sine generatorand said housing to dampen the effect on said housing of the sinusoidalvibration applied to said spindle by said sine generator.
 2. A vibratorydrill head according to claim 1 wherein each of said eccentric rotorsincludes an inside face wherein said inside faces of said six eccentricrotors substantially define an aperture and said spindle passes throughsaid aperture.
 3. A vibratory drill head according to claim 1 whereinsaid spindle protrudes outside said housing.
 4. A vibratory drill headaccording to claim 1 wherein said material is selected from the groupconsisting of cuttings, instrumentation, and drill tooling.
 5. Avibratory drill head according to claim 1 wherein rotation of saidspindle about a spindle axis is effected independently of the operationof said sine generator.
 6. A vibratory drill head according to claim 1wherein said spindle being adapted for connection to a drill bit toeffect a sonic drilling mode when said spindle is driven at a firstspeed and a rotary drilling mode when said spindle is driven at a secondspeed greater than said first speed.
 7. A vibratory drill head accordingto claim 1 wherein said spindle rotates independently of said sinegenerator.
 8. A vibratory drill head according to claim 7 furthercomprising an anti-rotation assembly to prevent rotational displacementof said sine generator.